Articles in 2022

A photonic quantum heat engine based on superradiance — many-atom quantum coherence — is shown to deliver enhanced operation, with an efficiency no longer bounded by the Carnot limit.

Temporal compression of optical waveforms with compression factors up to 13,000 is demonstrated by exploiting four-wave mixing in a birefringent fibre.

Nitrogen-vacancy centres in surface-engineered diamond are demonstrated to operate as charge-sensitive fluorescent reporters, enabling an optical scheme for voltage recording in physical and biological systems.

Optical clearing based on ultrasound-induced gas bubbles offers new opportunities for deeper laser scanning microscopy of biological tissue.

In-fibre second-harmonic generation is demonstrated in all-silica optical fibres by growing MoS₂ monolayers directly onto the fibre’s core.

Ultrafast wavepackets are generated featuring precise correlations between spatial and temporal properties.

Under near-infrared-light excitation, anti-Stokes-shift superfluorescence is observed near 590 nm at room temperature in a medium of lanthanide-doped upconversion nanoparticles. The spectral width and radiative decay lifetime are 2 nm and 46 ns, respectively, in the single-nanoparticle case.

A double-ring-resonator device on thin-film lithium niobate enables the generation of electro-optic frequency combs with a 30% power efficiency and an optical span of 132 nm.

Multilayered ferroelectric NbOI₂ crystals with sub-100-nm thickness exhibit efficient second harmonic generation, paving the way for on-chip nonlinear optical components.

A new method enables precise control of spin qubits in diamond by selectively activating them with a laser beam, thus paving the way to the control of spin qubits in dense arrays for applications in quantum technology.

The hardest barrier in the way to topological control over light with magnetic fields is extremely weak magneto-optic coupling. Now, strong light-matter coupling in an optical cavity has been used to reach record energy splitting values for photonic spins in magnetic fields. This is a potential game changer for topological photonics.

Researchers demonstrated a gate-tunable graphene photodetector with a bandwidth of up to 220 GHz. This was achieved by suppressing the ‘RC’ time constant using a resistive zinc oxide top gate.

Researchers demonstrate efficient frequency conversion with rhombohedral MoS₂. A second-harmonic-generation coherence length of ~530 nm at 1,520 nm wavelength and giant nonlinear optical enhancement in waveguide geometries are reported.

An ultrabroadband femtosecond enhancement cavity is developed, using gold-coated mirrors and a wedged-diamond-plate input coupler. Simultaneous enhancement of a 22–40 THz offset-free frequency comb allows cavity-enhanced time-domain spectroscopy of gas mixtures based on electro-optic sampling in the mid-infrared range.

The presence of topologically protected edge states is usually determined by angular-resolved photoelectron spectroscopy, requiring clean surfaces and ultrahigh vacuum. Now, an all-optical technique, based on high-harmonic radiation, has been shown to detect topological phase transitions under ambient conditions.

Researchers demonstrate a method based on circularly polarized laser-field-driven high-harmonic generation for probing non-trivial and trivial topological phases in a three-dimensional topological insulator.

Optical fibres can now directly generate a variety of Bessel beams thanks to custom-designed, intricate 3D-printed structures applied to their tips.

Gabriel Popescu passed away in June 2022. He will be remembered as a creative leader in biophotonics, with pioneering contributions to quantitative phase imaging and spectroscopy, an engaging collaborator and a dear friend.

Up to six photons in a Greenberger–Horne–Zeilinger state are sequentially generated by using a Rydberg superatom—a mesoscopic atomic ensemble under the condition of strong Rydberg blockade. The efficiency scaling factor for adding one photon is 0.27.